Server-Side Stitching: How Publishers Are Bypassing Ad Blockers And Avoiding Video Latency

StitchServer-side ad insertion (SSAI), also known as ad stitching, is emerging as a key method for video publishers to mitigate ad blocking and boost video playback across devices.

Though the technique is not new, industry insiders say there is massive growth potential as consumers stream more video content and new over-the-top devices enter the fray.

“The benefit for us is gaining a TV-like asset across all streams, which gives the advertisements a crystal-clear effect,” said Jarred Wilichinsky, VP of video monetization and operations for CBS Digital Media at CBS Interactive. “Delivering a super-pixelated asset does not make we as broadcasters shine, nor our advertiser.”

Publishers can stitch video content and ads together in a single pod on the server side, essentially allowing them to bypass browser or device-level integrations.

This streamlines the ad-delivery process because ads are stitched to content on the back end through a single source in the cloud, rather than requiring a publisher to build individual SDKs across disparate devices (Roku, Apple TV), file formats (Apple’s HTTP Live Streaming, “HLS” playback) or operating systems (iOS, Android).

CBS has taken the server-side approach to ad stitching for several years, beginning in 2012 as a strategy for mobile. It was a move that allowed the broadcaster to avail video streaming service CBS All Access across myriad devices, ranging from Amazon Fire TV to Roku – fast. 

CBSi“People are looking to remove friction in the mobile and over-the-top environment and make it more of a TV-like experience,” added Mike Green, a VP at Brightcove, which offers an SSAI solution. “Issues arise in client-side scenarios where one call is made for an ad and another to render content, which results in those spinning wheels or delays. People are looking to remove that friction.”

In addition to Brightcove, a number of other providers offer SSAI solutions for video, including Comcast’s FreeWheel, Google’s mDialog, Anvato, Verizon Digital Media Services and Adobe/Auditude, which is now known as Adobe Primetime.

These services typically integrate with a publisher or broadcaster’s ad server, such as DoubleClick For Publishers, FreeWheel or SpotX, pre-populate ads and stitch them into content in real time.

Think of server-side ad insertion like a direct flight, and client-side insertion as the connecting flight. Both serve the same purpose, ultimately, but the latter introduces greater probability for delays or lost luggage.

Use Cases For SSAI

Since premium video formats can command high CPMs from advertisers, publishers want to ensure those ads are rendered and under reasonable parameters that ensure they meet viewability thresholds.

Server-side stitching can leave ad blockers shooting in the dark, one added benefit of the technique. Ralf Jacob, CRO of Verizon Digital Media Services, called client-side ad insertion “prey” for ad blockers.

When a browser or device-level script makes a call to the ad-decisioning system, the ad blocker can identify that signal, as opposed to a server-side script where the ads are already stitched into the player’s content, making it harder to distinguish an ad from content, he said.

alexServer-side ad insertion essentially creates one stream that leaves ad blockers blind to other domains that are being called, said Alex Calic, CRO at The Media Trust, a company that monitors ad quality.

“If the domain is just ‘,’ they’re not going to block that because it looks just like content even though there may be an ad at the beginning or end of content,” Calic said.

Server-side ad insertion also profoundly improves the user, programmer, publisher and advertiser experience. Vox Media had virtually given up on monetizing mobile web for Android audiences because HLS playback for video content and pre-roll was so problematic on these devices.

Vox used Brightcove’s server-side ad insertion tool, Lift, to stitch ads to video content on the back end, rather than relying on individual client calls that resulted in faulty HLS playback.

“In the case of Vox, it was about improving the user experience and opening up additional monetization for mobile web,” said Brightcove’s Green. “They have a lot of young, male-leaning properties, like Polygon for gamers, and Verge for tech, [so] I assume they have a very sizable ad-blocking audience. That, however, wasn’t the reason they came to us.”

mgESPN, too, didn’t monetize mobile Web for some time because of similar challenges.

If a user wanted to watch SportsCenter’s top 10 highlights, ESPN would redirect that user to the mobile app because it didn’t support a mobile web experience, leading some users to drop off. Server-side ad insertion opened up new mobile web monetization potential for ESPN and subsequently smoothed out the user experience.

Limitations of SSAI

Because SSAI essentially rewrites the way many third-party video ad servers, measurement and delivery systems communicate, it can require a lot of heavy lifting from a publisher’s internal ad ops team or require external vendor support.

Thus, it may be a more useful technique for a specific subset of publishers.

“Because ads are pre-populated into the content itself, it might work better for direct, sponsorship-based content as opposed to programmatic auctions, which require real-time decisioning,” predicted The Media Trust’s Calic.

VFor instance, a publisher like Refinery29 or BuzzFeed that produces a lot of video content and primarily relies on direct deals might benefit most from ad stitching, he hypothesized.

Since segments tend to be pre-defined prior to insertion into the ad pod server-side, there may arguably be less room for audience discovery or competitive pricing for direct deals than in a programmatic auction.

Additionally, because SSAI mimics commercial broadcast delivery in a digital environment, it may benefit most when applied in video on-demand or other time-shifted formats.

Some argue that client-side technology still adds a necessary level of interactivity and support for live content, though platforms with advanced capabilities claim they can usually work out these kinks.

Other advancements, such as the IAB’s release of a new Video Ad Serving Template 4.0 (VAST 4.0) also support server-side ad insertion, said CBSi’s Wilichinsky.

Matt“The VAST 4.0 file type is a huge move,” he added. “In the online world, standardizing around the metadata component allows us to talk to the same user across different [devices] on the same terms” through a single creative.

Ultimately, publishers want greater flexibility to enable dynamic ad insertion within disparate video streams.

“This is helping big publishers take their episodic TV content and condition it so it can be distributed to their website, apps or on-demand destinations they may syndicate to, such as Netflix or Hulu,” said Matt Smith, chief evangelist for Anvato, an SSAI vendor.

“Simplifying the way we prepare this content and, hence, monetize it drives tremendous efficiencies. It also solves frustrations for consumers who see the same ad over and over again in ad breaks.”


  1. Great article Kelly. VAST 4.0 spec is a great step to standardise server side ad insertion, I only hope that video platforms adapt it quicker than they did VAST 3.0, otherwise it'll be years before the industry can reap the benefits and create the scale.

  2. This is a solid solution for video. Though, an abuse of advertising by a publisher using server side stitching could lead to the entire video feed (or site) being blocked. In a similar fashion (though not as easy), I'd love to see more server to server integrations in the display world too.


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